SHALLOW DETACHMENT AT THE TOE OF THE EASTERN NANKAI ACCRETIONARY WEDGE REVISITED, NEW INSIGHTS FROM A DEEP-TOW SAR PASISAR SURVEY (KAIKO-TOKAI 1996 CRUISE)/

To better define the tectonic context of the venting sites at the toe of the Eastern Nankai accretionary complex, the deep-tow side-scan son ar and seismics 'KAIKO-TOKAI' cruise revisited the KAIKO-NANKAI ventin g sites during the Spring 1996 on board R/V L'Atalante. The results of the cruise enable us to confirm the existence of an internal deformat ion of the first thrust unit expressed as a mini-accretionary wedge ab ove a shallow decollement. Some vents near the top of the frontal anti cline may be related to fluids flowing through the shallow decollement , whereas others cannot. These observations raise the question of the respective role of faults, permeable stratigraphic conduits and fractu red strata in the flow of fluids. (C) Academie des sciences/Elsevier, Paris.